Provided are a reception device, a reception method and a transmission reception system capable of reducing the influence of distortion in a received signal and achieving high demodulation performance without performing a computation process having a great amount of calculations. The reception device receives a signal containing a known signal part and a data part, and includes a conversion unit that converts the signal received by a reception unit into a digital signal, a region determination unit that determines a nonuse region which is a periodic region containing distortion in the digital signal, on a basis of a first digital signal in the known signal part contained in the digital signal and a known signal held in advance, and a demodulation unit that performs demodulation on the digital signal by using a second digital signal in a region other than the nonuse region in the digital signal.

Embodiments may provide a way of communicating via an electromagnetic radiator, or light source, that can be amplitude modulated such as light emitting diode (LED) lighting and receivers or detectors that can determine data from light received from the amplitude modulated electromagnetic radiator. Some embodiments may provide a method of transmitting/encoding data via modulated LED lighting and other embodiments may provide receiving/decoding data from the modulated LED lighting by means of a device with a low sampling frequency such as a relatively inexpensive camera (as might be found in a smart phone). Some embodiments are intended for indoor navigation via photogrammetry (i.e., image processing) using self-identifying LED light anchors. In many embodiments, the data signal may be communicated via the light source at amplitude modulating frequencies such that the resulting flicker is not perceivable to the human eye.

Embodiments of this application provide a data transmission method and apparatus. A method at a transmit end includes: obtaining a first sequence, where the first sequence includes a first sub-sequence and a second sub-sequence; mapping the first sub-sequence into K third sub-sequences based on a preset sequence group; performing differential coding and phase modulation on the second sub-sequence to obtain a fourth sequence whose length is K′; obtaining K fifth sub-sequences based on the K third sub-sequences and the K′ fourth sub-sequences; and outputting a second sequence including the K fifth sub-sequences. A method at a receive end includes: obtaining a second sequence including K fifth sub-sequences, and detecting the K fifth sub-sequences based on a preset sequence group to obtain a first sub-sequence; and performing differential demodulation based on the first sub-sequence to obtain a second sub-sequence, so that a first sequence is determined.

Embodiments of this application provide a data transmission method and apparatus. A method at a transmit end includes: obtaining a first sequence, where the first sequence includes a first sub-sequence and a second sub-sequence; mapping the first sub-sequence into K third sub-sequences based on a preset sequence group; performing differential coding and phase modulation on the second sub-sequence to obtain a fourth sequence whose length is K′; obtaining K fifth sub-sequences based on the K third sub-sequences and the K′ fourth sub-sequences; and outputting a second sequence including the K fifth sub-sequences. A method at a receive end includes: obtaining a second sequence including K fifth sub-sequences, and detecting the K fifth sub-sequences based on a preset sequence group to obtain a first sub-sequence; and performing differential demodulation based on the first sub-sequence to obtain a second sub-sequence, so that a first sequence is determined.

A system and module for, and a method of correcting, memory misalignment in a phase shift keying receiver is disclosed. Embodiments include a system having: an analog front end for receiving a demodulated signal having a preamble portion, and for generating a digital register input signal including a received preamble portion; a finite state machine for selecting a memory address of the demodulated signal based on the received preamble portion; a preamble memory for storing all possible preambles contained within the demodulated signal and for supplying a selected preamble memory output corresponding to the selected memory address; and a memory alignment module configured to compare phase information of symbols of the preamble portion and preamble phase information of symbols of the selected preamble memory output. This system checks that the preamble portion of the register input signal aligns with the selected preamble memory output and makes corrections when necessary.

A method, system and computer readable medium for transmitting data and feedback over a noisy feedforward channel and a noisy feedback channel.

A method of operating a transmitter (FIGS. 3A and 5A) is disclosed. The method includes receiving a sequence of data bits (DATA), wherein each data bit has a respective sequence number. A first data bit of the sequence is spread (508) with a first spreading code (504) determined by the sequence number (502) of the first data bit. A second data bit of the sequence is spread (508) with an inverse of the first spreading code (506) determined by the sequence number (502) of the second data bit. The first and second data bits are modulated (510) and transmitted (516) to a remote receiver.

A method of operating a transmitter (FIGS. 3A and 5A) is disclosed. The method includes receiving a sequence of data bits (DATA), wherein each data bit has a respective sequence number. A first data bit of the sequence is spread (508) with a first spreading code (504) determined by the sequence number (502) of the first data bit. A second data bit of the sequence is spread (508) with an inverse of the first spreading code (506) determined by the sequence number (502) of the second data bit. The first and second data bits are modulated (510) and transmitted (516) to a remote receiver.

A correlating mixed signal spectrum analyzer receiver is provided that automatically correlates signals in a mixed-signal environment with a large number of waveforms having different characteristics corresponding to different protocols and modulation types, with the receiver utilizing either parallel correlators or sequential correlations to automatically accommodate the different waveforms such that in any given testing cycle, the spectrum analyzer runs through a comprehensive list of waveforms to detect the existence of corresponding signals. Frequency drift compensation and the utilization of multiple receivers for providing time difference of arrival calculations is described.

A method and apparatus for underwater acoustic communication are disclosed. A data packet frame structure in the communication transmission includes a preamble, a synchronization code, and a data code. A guard interval is disposed between the preamble and the synchronization code. This method utilizes the different impact response environments of linear frequency modulation signals in different frequency bands to obtain the mapping relationships corresponding to the characteristics of the impulse responses in the frequency band, and adopts the quadrature phase shift keying (QPSK) modulation method to convert four groups of LMF signals with different center frequencies and the same modulation frequency, representing different symbols for signal transmission, where the LFM carrier signal of each center frequency can represent two bits of binary information to improve transmission efficiency. The apparatus for underwater acoustic communication also has the above-mentioned technical effects.